from
The Collaborative International Dictionary of English v.0.48
Oscillate \Os"cil*late\ ([o^]s"s[i^]l*l[=a]t), v. i. [imp. & p.
p. {Oscillated} ([o^]s"s[i^]l*l[=a]`t[e^]d); p. pr. & vb. n.
{Oscillating} ([o^]s"s[i^]l*l[=a]`t[i^]ng).] [L. oscillare to
swing, fr. oscillum a swing, a little mask or puppet made to
be hung from trees and swing in the wind, prob. orig., a
little mouth, a dim. from os mouth. See {Oral}, and cf.
{Osculate}.]
[1913 Webster]
1. To move backward and forward; to vibrate like a pendulum;
to swing; to sway.
[1913 Webster]
2. To vary or fluctuate between fixed limits; to act or move
in a fickle or fluctuating manner; to change repeatedly,
back and forth.
[1913 Webster]
The amount of superior families oscillates rather
than changes, that is, it fluctuates within fixed
limits. --De Quincey.
[1913 Webster]